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Calculation of the radius of gyration (K²) for car model 11-G-111 (landaulet body) by swinging.


Identifier  ExFiles\Box 107\4\  scan0088
Date  16th January 1928 guessed
  
X-4538

TO FIND K² FOR 11-G-111 BY SWINGING. X5830
(LANDAULET BODY, SPARE WHEEL AT REAR).

Let K²_GT = K² of total car (including axles) about c.g. of total car.
= T² pg / 4 π 2 - p² ft²

Where p = distance of c.g. from point of support when swinging
= 10.167'

T = 3.9 secs.

Ther K²_GT = 22.6 ft².

Weight of total car = 4004 lbs.

∴ I_GT = 4004 X 22.6 = 90,500 lbs.ft².

From this must be subtracted the axle inertias about the same point.

Weights are ( Front 305 lbs. k² = 1² + 6.083²
( Rear 485 lbs. k² = 1² + 4.708²

Inertia for two = 305 (1² + 6.083²) + 485 (1² + 4.708²)
= 22,840 lbs.ft².

∴ I_G = Inertia of spring part about c.g. of spring + unsprung parts
= 67,660 lbs.ft².

Weight of sprung part = 3214 lbs.

∴ k²_G = 67,660 / 3214 = 21.06 ft².

To find position of c.g. of sprung part.

contd :-
  
  
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).


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